Surface evaporator made of fumed silica, for concentrating or evaporation of acids and other liquid chemicals. By indirect heating by means of infrared radiation no stormy boiling and splashing. Resistant to aggressive media. A fused quartz glass-sheathed, helical, electric heating coil with a large surface, mounted in a quartz material reflector shell with handle, allows indirect heating of liquids by infrared radiation. This serves for rapid, economical evaporation or concentration of liquids. Due to this principle, only the surface of the liquid is very strongly heated, since the heat radiation is already absorbed after a small penetration depth, thus enabling gentle, even evaporation. In contrast to the boiling evaporation, there is no loss of substance due to splashes of a moving boiling Surface. Since surface evaporators are made exclusively from the quartz material / glass material, it is possible to use the advantages of the material such as good IR-permeability, heat and heat exchange resistance, minimum electrical conductivity, exceptionally high chemical purity and resistance as material. These material advantages allow gentle evaporation of acids and other liquid chemicals. Except are hydrofluoric acid, phosphoric acid and liquids with high alkalinity. Electrical safety: The jacket made of quartz material is an excellent electrical insulator - safe contact protection, optimum electrical safety by grounding the interior. The surface evaporators comply with the EC Directive 89/336 / EEC and the EC Directive 73/23 / EEC.